1. Field of the Invention
The present invention relates to a method and apparatus for packing bagged products, or more precisely a method and apparatus for automatically packing so called flexible packages containing snack foods or the like (hereinafter referred to as "bags") into a container while bags are in condition to be aligned and overlap each other partially.
2. Prior Art
When transporting, storing or handling bags, it is necessary to pack a set quantity of bags into a container such as a corrugated carton. Although packing bags in a carton or the like has been universal, it is a fact that no satisfactory method or apparatus for packing bags is known or developed with a view to protecting the contents, as will now be described.
There are many problems in packaging and packing bags, especially bags of snack foods or the like, since snack foods such as potato chips, pop corn, corn chips or the like have the common characteristic that they can be easily damaged, absorb moisture, their flavour may be changed, etc. In particular, that they can be easily damaged presents the biggest problem. To be more precise, since snack food packages are not even in shape with concavo-convex and they have a large surface area, the likehood of the contents being damaged during the time from when products have been shipped from manufacturers to when they reach consumers through various kinds of distribution passages, thereby consequent deterioration of commodity value can frequently occur.
To prevent this from happening at the present time a certain amount of air, nitrogen gas or the like, is enclosed with the bag together with the contents, when bagging the products. However, bags in which air or gas is enclosed together with goods are bulky and packing of such balloon-like bags into a carton can only be carried out manually, since these bags need to be partially overlapped when packing. In addition, a bag within which air or gas is enclosed gradually shrinks and reduces size thereof with the decreasing temperature of said products after packing. Furthermore, it is inevitable that air or gas enclosed in a bag, although it depends on air tightness or sealing capability thereof, gradually leaks during the duration of distribution thereof. Under the above mentioned circumstances, the size of the bag is gradually reduced, after being packed, and gaps between bags within the carton frequently occur.
Presently apparatus for packing bags automatically is conventionally known; for example, see Japanese Laid Open Publication Nos. Showa 59-134105 or Showa 60-23105. However, since that invention relates to a method of packing bags into a carton one by one to be overlapped with each other partially through a belt conveyor, therefore, it is neither efficient to handle a large number of bags at a time nor suitable for handling many bags at high speed. Moreover, the former invention was developed for packing relatively heavy goods such as "instant" fresh noodles, and therefore is not suitable for packing flexible packages because flexible packages are light weight and tend to suspend by air resistance when an attempt is made to drop packages in a set position, resulting in dislocation.
On the other hand, in the latter apparatus, using a motion arm equipped with vacuum pads, bags fed by a loading conveyor are transmitted onto a carton while by the arm keeping suction, and drops the bags into a carton by releasing suction of the pads. This method requires a bigger carton since a bag drops aslant if even a corner of the bag touches the edge of the carton. This results in a gap between bags after packing.
For the reasons of efficiency and economy, it is desirable to pack bags as tightly as possible into a carton in order to avoid gaps between bags especially when bags reduce their size after being packed and shrunk. However it is not able to carry out such tight packing and consequently there is no choice but to do it manually.
Recently a method has been proposed that uses an actuator like a robot affixed with vacuum pads, and the plural bags fed by a belt conveyor are picked up by the vacuum pads, turned to one side or transfered horizontally, and then the actuator is lowered to pack the bags into a carton. However, in this method, it is necessary to have 3 discontinuous motions for picking up, lowering down and turning bags by an actuator, resetting in inconvenience with extremely slow operational speed, and therefore it has inferior operation efficiency.